1. Field of the Invention
This invention relates generally to golf, specifically to mats which are used for teeing golf balls.
2. Description of Prior Art
Golf balls are ordinarily hit off grass turf, but during practice at the driving range and sometimes on the golf course when turf conditions are bad it is common to hit balls from a mat. Golf clubs scrape or cut turf from the ground and the golfer's feet destroy the turf when the same spot is used over and over. Consequently, small or heavily-used driving ranges employ mats to provide hitting and standing surfaces that withstand concentrated use.
Some mats are only for standing on--stance mats--while others are for club contact--teeing mats. Some serve both functions.
Heretofore, mats have been plagued by a number of problems. Some mats snag and decelerate a clubhead to an unacceptable degree, even completely stopping a clubhead. This sometimes causes injury to the golfer. The cause of snagging is not today's short-bristled artificial turf per se, but the way it is mounted and the way it delaminates. When artificial turf delaminates or separates from the layer below it, it can wrinkle in front of an impacting clubhead and snag the clubhead. A strong blow eventually rips the delaminated portion. This occurs on the large mats that are popular today.
Another problem is bouncing of the clubhead off the mat. Poplular mats have no cushioning or a very high spring rate of cushioning. On real turf, a clubhead cuts through the grass and soil. The clubhead is supposed to strike the turf after hitting the ball. Mats bounce the clubhead when the golfer swings with the downward stroke used on real turf. Consequently, golfers often adjust their swings to give a glancing blow to the mat instead of hitting down into it. This adjusted swing is not providing practice of the swing that most golfers want to use on the course, nor is the adjusted swing easy to produce. To avoid contact with the mat, overadjustment of the swing leads to millions of ruined shots and damaged balls where the sharp lower edge of the clubhead hits the ball first. Moreover, if a clubhead hits behind the ball on real turf, the golfer is penalized by loss of distance and poor contact with the ball. On a mat, a bounce of the clubhead off the mat behind the ball can result in a solid hit without the golfer's awareness of the bounce. If this mistake recurs without correction, the golfer may be unhappily suprised at the next use of real turf.
On driving ranges today, one can find basically two kinds of mats: One, a small uncushioned teeing mat of artificial turf bonded into a hard thin rubber casting which is in turn cradled in a larger hard thin rubber casting; two, a plain large mat, used for both teeing and standing, made of artificial turf with about 1.9 cm (3/4 inch) of dense foam (having a 50% compression deflection of around 700 to 1400 grams/sq. cm (10 to 20 Lbs/psi)) bonded under it, with a net or scrim interface bonded between the two layers. A large plain mat with cushioning deflects perhaps 0.25 cm (0.1 inch) under a weight of 5.45 kgrams (12 lbs). A small uncushioned mat with a rubber base virtually does not deflect (except among the bristles of its artificial turf). Both types bounce a descending clubhead, and both delaminate. The large cushioned mats delaminate in spot after spot, wrinkle, snag the clubhead, and soon rip on a regular schedule.
The large mats have a special undesirable feature. Even when hitting from a spot that has not yet delaminated, a very short-lived but intense deceleration of the clubhead takes place when the clubhead tries to descend below the bristle level of the mat. This deceleration not only feels unnatural and wears out the mat, it also masks the feeling of the ball compressing against the clubface, thereby reducing the golfer's pleasure and feedback regarding solidity of the hit.
Mats usually have a hole for a common rubber tee to be inserted from below and on which a ball is placed so that a special shot, the drive, may be made. The rubber tee elevates the ball above the mat surface. Rubber tees wear too quickly because they get pinched against the mat.
Golfers consistently berate golf practice mats. Driving range operators are eager to have more durable and/or less expensive mats.